CIGRE Working Group concludes Demand forecasting study

By ANC, 19 December 2016

Working Group C1.32, Establishing Best Practice Approaches For Developing Credible Electricity Demand And Energy Forecasts For Network Planning

Load forecasts are used across the industry for both long term and operational planning. They form a critical input into infrastructure investment decisions. These investments can be tens or hundreds of millions of dollars and there are numerous examples where industry has been criticised for investing too soon or too late.

With this in mind, CIGRE Working Group C1.32 carried out a survey of international utilities to establish best practice approaches for developing electricity load and energy forecasts. A total of 29 fully completed surveys were available for analysis. The respondents represent 18 countries. Most respondents come from Oceania (10 responses), Asia, and Europe (8 responses each). One response was received from Africa, North America, and South America each.

The forecasts are mainly used for long-term grid planning; in 40% of these 23 cases the responses also apply for short-term operational planning. In 18% of the cases, the forecast was also used for generation development; in 21%, for security of supply; and in 29% also for generation adequacy studies. The timing of the peak load is evenly spread: 50% of the respondents work in a country or region with a peak load in winter and 44% in summer.

In most cases both load and energy are forecast. 36% of the forecasts were for load only. No forecasts focused solely on energy. Almost all forecasts are required by regulation, yet in most cases regulation does not prescribe the methodology. Most respondents used load and energy forecasting software that was developed in-house.

Most respondents do not explicitly forecast reactive power. Reactive power is often indirectly forecast based on assumed or historic values of power factors.

Most forecasting teams (56%) consist of a small group of up to 5 people.

The forecast methodology is frequently revised. Most respondents revised it in the last 2 years (53%) and of this group almost all are also planning to revise again in the next 2 years (88%). For those who reviewed the methodology more than 2 years ago, most also plan to revise again in the next years.

Given that forecast methodologies are frequently reviewed, it seems that best practice in forecast methodologies is not widely agreed (at least amongst the survey respondents). Some aspects where there are common approaches are the modelling of load by type (e.g. residential, commercial, industrial), using a combination of top down and bottom approaches to forecasting and forecast horizons (e.g. most long term forecasts look ahead 5 to 15 years).

Survey respondents identified the most important aspects to improve in the forecast method: